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Removing/Preventing graphite from sticking to Kovar

Q. I have an operation that requires Kovar electrodes to be placed in a graphite jig while going through a furnace at approximately 2000F. Everything is fine except for intermittent splotches of carbon sticking to the metal. Has anyone seen a way to remove or prevent this type of problem, and does anyone understand why this happens? Currently, we buff the graphite off, but it produces an undesirable surface finish.

Any help/suggestions would be appreciated.

Thanks,

Mark Bramble
- Preston, Maryland, USA
2003

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Q. It's an increasingly important issue here as well, and and trying to come up with a solution that does not require some sort of physical polishing has been elusive.
I've been thinking more along the lines of some sort of pre-treatment of the kovar prior to baking (boron nitride, perhaps?). I'm also looking at a combination of organic acids as a clean without damaging the kovar. I don't know if some sort of anodic electroclean would work, but it may be worth looking into as well.
Believe me when I say I know how you feel!

Robert Belter
- San Diego, California, USA
August 26, 2013